Piano sounding board



Jan. 14, 1936.

H. FiscHER 2,627,969

PIANO SOUNDING BOARD Filed Sept. 9, 1953 @www Patented Jan. 14, 1936Application September 9, 1933, Serial No. 688,763

UNITED STATES PATENT GFFICE 3 Claims.

My invention relates to an improvement in sounding boards and isapplicable for example to piano sounding boards. Gne object is theimprovement of the vibration characteristics of a piano sounding board,for example by conveying the vibration from the bridge oi the soundingboard out into the free and open part of the board. This effects animprovement in the tone of the sounding board and therefore of the pianoand is a method oi even tone distribution. Another object is theimproved supporting or reinforcing means for a piano sounding board,including for example forming the reinforcing ribs with chamieredportions having a delinite relation to the location of the bridge orbridges on the sounding board. Other objects will appear from time totime in the course of the specification and claims.

I illustrate my invention more or less diagrammatically in theaccompanying drawing, wherein- Figure l is a plan View;

Figure 2 is a section on the line 2-2 of Figure 1;

Figure 3 is a section on the line 3 3 of Figure 2; and

Figure 4 is a View of the piano and sounding board from below.

Like parts are indicated by like symbols throughout the specificationand drawing.

A generally indicates any suitable outer frame or supporting means orhousing of a piano, it being understood that the piano details do not cithemselves form part of the present invention. I illustrate for exampleforward legsY A1, a rear or end leg A2, for supporting the piano, andthe usual keys A3.

B is the sounding board proper of the piano, the board being of anysuitable wood or vibrating material, However, I prefer to employ spruce.Positioned above the sounding board is the bass bridge generallyindicated as B1 and the treble bridge generally indicated as B2, thetreble bridge B2 extending substantially across the entire width of thesounding board. Any suitable wires B3 may be employed, secured in anysuitable fashion and operated upon by any suitable percussion mechanismresponsive to movement of the keys A3. As such features do not ofthemselves form part of the present invention they are not herein shownin detail.

Positioned upon the upper surface of the sounding board B is a vibrationdistributing member generally indicated as C which may be a relativelythin and irregularly shaped piece of wood, for example spruce, which issecurely fastened, cemented, or glued to the sounding board so that thetwo are in effect one piece. Preferably, both sounding board and theextra vibrating or vibration distributing member are made of the samewood, namely spruce. Preferably, the grain of the part C is parallelwith the grain of the sounding board B, the grain in both casesextending transversely across the axes or longitudinal extensions of thestrings B3. The member C underlies the treble bridge B2, which may besecured to it and through it to the sounding board B. It includes aplurality of portions forwardly extending from the bridge. I illustratefor example an end portion C1, and intermediate extensions C2, C3 andC4.

In effect, what I am doing is to thicken the sounding board proper andto provide thickened portions which extend from the bridge out into theopen body or expanse of the sounding board, these thickened portionsbeing free to vibrate with the sounding board and being of parallelgrain therewith. In practice the eiTect is to distribute Vibrationthroughout the sounding board and to cause the sounding board aseJ wholeto vibrate to obtain the maximum strength and purity of tone in responseto the vibration of the wire or wires struck by the percussivemechanism.

I also iind it advantageous o chamfer or thin the plurality ofstrengthening ribs employed for the bottom of the sounding board. Iillustrate for example a plurality of ribs D chamfered at the ends as atD1. It will be noted that the chamfered end portions are oi varyinglength and the higher intermediate portions D also are of varyinglength, the treble bridge B2 extending across the thickest portions ofthe ribs D.

It will be realized that whereas I have shown a practical and operativedevice, nevertheless many changes might be made in the size, shape,number and disposition of parts without departing from the spirit of myinvention. I therefore Wish my description and drawing to be taken as ina broad sense illustrative and diagrammatic rather than as limiting meto my specific showing.

The use and operation of my invention are as follows:

In my device I employ the conventional piano sounding board or itsequivalent, which I form of spruce. I find that the tone and vibrationdistribution are very much improved if, instead of having a flatsounding board or a sounding` board of uniform thickness, I associate,with the bridges or with one of the bridges, a thickened portion, anextra vibrating portion, generally indicated as C, having parts, such asC2, C3, C4, which extend outwardly away from the. bridges, and whichtend to lead or distribute the vibration caused by the hammers on thestrings, out into the body of the sounding board. In practice I make thebridges of maple, the supporting or reinforcing ribs D of spruce and thesounding board B and the extra vibrating portion C also of spruce. Ineffect, the member C is a thickening of the memberB, being cemented orglued to it and under some circumstances this thickening might beobtained by simply carving out or reducing the thickness of the soundingboard B. I nd it easier, however, and more practical, to obtain thedesired variation in thickness by adding the Vibrating portion C.

I claim:

l. In combination with a piano sounding board, a bridge, wiresassociated with said bridge and a layer of Vibration transmittingmaterial interposed between said bridge and sounding board and firmlysecured to said sounding board, both sounding board and layer being ofwood, the grain of both extending, in

general parallelism, transversely across the wires.

2. In combination with a piano sounding board, a bridge, wiresassociated with said bridge' and a layer of vibration transmittingmaterial interposed between said bridge and sounding board and firmlysecured to said sounding board and abutting thereagainst, throughout theentire area of said layer, both sounding board and layer being of Wood,the grain of both extending, in general parallelism, transversely acrossthe wires, said layer including a plurality of projections extendingtransversely of the wires.

3. In combination with a piano sounding board, a bridge, wiresassociated with said bridge, and a layer of vibration transmittingmaterial interposed between said bridge and sounding board and abuttingagainst and iirmly secured to the sounding board, said layer beingfirmly secured, throughout its area,' to said sounding board, said layerincluding a plurality of projections extending outwardly away from thebridge, the sounding board and said layer being formed of the same wood,the grain of both extending in general parallelism.

HERMANN FISCHER.

